Alcoholic and aqueous extract of tuberous roots of Corallocarpus epigaeus (CE) were prepared and given individually orally at different doses to different groups of rats fasted for 18 h (both normal and streptozotocin (STZ) induced diabetic albino rats). The serum glucose levels were measured initially at 0 h (before treatment) and at 0.5, 1, 2, 3, 4, 6, 8, 12, 16, 20 and 24 h after the treatment. The alcoholic extract of tuberous roots of C. epigaeus (AETRCE) at medium dose (60 mg/kg) and higher dose (80 mg/kg) produced maximal serum glucose lowering effect in both normal and STZ induced diabetic rats. The aqueous extract of tuberous roots of C. epigaeus (AQETRCE) produced maximal percent reduction in serum glucose levels with higher dose (400 mg/kg). AETRCE and AQETRCE produced biphasic response with peak hypoglycemic and antidiabetic activities recorded out at 4 h and 8 h intervals in normal and STZ induced diabetic rats in a dose dependent manner. These effects were found to be better than that of standard gliclazide (2 mg/kg) an oral hypoglycemic agent.